Adjusting device for rolling mills



2 Sheets-Sheet 1 P. BLAIN ADJUSTING DEVICE FOR ROLLING MILLS Sept. 26,1950 Filed Aug. 9, 1946 Sept. 26, 1950 P. BLAlN 2,523,553

ADJUSTING DEVICE FOR ROLLING MILLS Filed Aug. 9, 1946 2 Sheets-Sheet 2 5L M I 7040A BLA/N Patented Sept. 20, 1950 ADJUSTING DEVICE FOR ROLLINGMILLS Paul Blaln, Paris, France, assignor to Soclete Anonyme desAoieries et Forges de Firminy, Paris, France, a body corporate or FranceApplication August 9,1948, Serial No. 889,861

In France January 29, 1946 My invention is concerned with a method ofcontrolling the pressure acting upon the rolls of a rolling mill for thepurpose of performing a given duty. for instance providing foruniformity in the thickness of the rolled material. This result isobtained primarily by means comprising a source or pressure fluid and ahydraulic squeezer-controlling relay so associated with the supply andthe discharge that practically it cannot be cut oil simultaneously fromboth. Thus,- the pressure within the squeezing jacks oi the rolling millis at all times either increasing or decreasing and each of these phasesin the operation oi the mill is quite briei' since it is almostimmediately brought to an end by the very excess in the pressure changeoccurring in the desired direction, which excess initiates a change inthe opposite direction. In this manner, without resorting to any specialmeans apart from the provision of a suitable connection of the relaywith the supply and the discharge respectively, the squeezing jack isconnected alternatingly and /1 Claim. (Ci. 80-58? at very small timeintervals with the supply and the discharge.

Am embodiment of the invention will now be described for the purpose ofexempliflcation and by no means of limitation in which the duty of thearrangement is to provide for uniformity in the thickness of thematerial worked upon; in the description reference will be had to'theappended in which- Figure l is a diagrammatical section taken on theaxis of the relay.

Figure 2 is a diagram showing the application of the method to the uniioo i w oi the rolling pre.

his. 3 shows the whole arrangement incorporating this improveddistributor.

Returning to Fig. 1, showing a conventional hydraulic irelay, II is thebody of the relay and t the piston. The body of the relay contains threepipe channels, one pipe t connected to the adlusting lack, one pipe tconnected to the water mains, and finally a thin one 5 connected to thedischarge. In line with the relative position of the piston and the bodyoi the relay, the adjusting jack is placed incommunication with thehigh-pressure water mains or with the discharge, the pipe leading to thejack being theoretically closed when the piston is in the position shownin Fig. i.

In fact, outside the periods of sharp change of load of the mill duringwhich the adjusting Jack is put in open connection with the highpressuremains or with the exhaust, the piston only changes its positionimperceptibly from the position shown by the figure; the pressure in theJack that is enforced by the working conditions of the mill is regulatedby the relay in the following way: a slight escape exists between thespace i in connection with the high-pressure mains and the space 8connected to the Jack; in the same way a slight escape exists betweenthe space it and the space 8 connected to the exhaust. An exceedinglysmall change of the position oi the piston 2 in the body I of the relaymodifies the load losses suflered by the fluid in the traverse throughone or the other or these throttlings, one of the load losses increasingwhen the other lessens. The pressure in the adjusting jack, comprisedbetween that of the highepressure mains and that Of the exhaust, is thusdefined by the position of the piston 2 in the body i; a very slightmodification of this position around the mean position shown on thefigure can during normal operation cause the pressure of the jack tovary between that of the highpressure mains and that of the exhaust:

It is possible to get the varying pressure that it is necessary toinitiate in the adjusting jacks of the mill, in order that the degree ofadjusting may correspond with the regulation called for, in a difierentway that, for certain forms of operation, will prove of greater interestthan the one just described.

The means for feeding the jacks, that is the object of my invention,consists in placing the jack, alternatively and at very short intervals,in communication with the high-pressure mains and with the exhaust.These alternatives of feeding and discharge cause slight fluctuations ofpressure in the Jacks, that, provided they are sumciently slight whichis so if the frequency of the feed and discharge intervals is largeenough, cannot prove a hindranc to the rolling, with the mean pressurestanding at a figure that depends only on the relative importance of theintervals of feed and discharge, it the pressure of the mains remainssteady.

Fig. 2 illustrates, as an example with no binding limits, 9, way ofapplying this method for regulating the pressure of the rolling. itdesignates the body of the distributor in which a piston II is adaptedto move. The body of the distributor contains thre tubular channels ofwhich one i2 connected to the adjusting jack, another it connected tothe high-pressure mains and finally a third marked HI that is connectedto the exhaust. The piston takes up two end positions in the distributorbody, that shown in accuse illustrated. the jack communicates with thehighpressure mains. In the other position, the jack connects with theexhaust. when working, the piston goes without stop from one of thepositions to the other in step with the impulses that are given by theelectromagnet,- the coil of which is closed or opened by a contactplaced tor instance on a contrivance for measuring the thick'- ness ofthe band, and this contact closes the circuit oi the electromagnet whenthe thickness goes beyond the set value and opens the circuit in theopposite case.

In the example that has been given of an application of the method forthe regulation of the rolling pressure, that is the obiect of myinvention, the adjusting jack is fed directly with high-pressure liquidby the distributor. It is possible, still keeping within the sphere ofmy invention, to act on the adjusting jack with the help 01' a hydraulicmultiplicator, while the distributor in this case supplies liquid atmedium pressure to the big cylinder of'the multiplicator, with the jackconnected to the small cylinder.

Fig. 3 illustrates what is the arrangement in this case 01' the controlmembers of the adjusting mechanism. In this figure, 20 designates a rollstand furnished with hydraulic adjusting jacks 2|. These Jacks are feddirectly by the highpressure end of a multiplicator 22 whose lowpressure end is connected alternatively with mains with medium pressure24 and with the exhaust by a distributor 23. The piston oi thedistributor is actuated by the electromagnet 25 in antagonism with thespring 20, and the contact that closes or opens the circuit of theelectromagnet is controlled by a contrivance for measuring thicknesses21.

This contrivance closes the circuit, thus starting a flow of liquidunder pressure to the adjusting jack when the thickness of the band goesover the set value. In the opposite case, the circuit is open. thusexhausting the jack.

What I claim as my invention and desire to secure by Letters Patent is:

In a rolling mill having opposed rolls adjustable toward and away fromone another, a control system for maintaining the thickness 01' therolled material substantially uniform comprising a source of pressurefluid, hydraulic means tor. tightening the rolls, a control valvecomprising a casing having spaced ports connected respectively to thesource of pressure fluid, the roll tightening means and an exhaust, avalve member freely reciprocable in said casing between a position inwhich the roll tightening means is connected with the source of pressurefluid and a position in which the roll tightening means is connectedwith the exhaust, an electromagnet for holding the valve member in oneof said positions when energized, means responsive to the thickness 01the rolled material for energizing said electromagnet upon predeterminedvariation 01 thickness or the rolled material, and spring means formoving said valve member to the other of said positions when theelectromagnet is deenergized and for holding it at said other positionuntil the electromagnet is reenergized.

PAUL BLAIN.

REFERENCES CITED The following references are of record in the UNITEDSTATES PATENTS Number Name Date 1,969,536 Winne Aug. 7, 1934 2,040,755Meyer May 12, 1936 2,267,380 Tyler Dec. 31, 1940

